Exhaust steam injector



Dec. 18, E RAWSQN EXHAUST STEAM INJECTOR Filed March 17, 1933 2 Sheets-Sheet 1 INVENTOR 5 74 1 05; /?/frYJ6/V awn,

ATTORNEY Dec. 18, 1934. wso I 1,984,547

EXHAUST STEAM INJECTOR Filed March 17, 1933 2 Sheets-Sheet 2 Ci-Kw ATTORNEY Patented Dec. 18, 1934 UNITED STATES PATENT OFFICE to YThe Super-heater Company, New York,

Application March 17, 1933, Serial No. 661,334

17 Claims.v (Cl. 103-265) The present invention relates to exhaust steam injectors. More particularly the invention relates to exhaust steam injectors of the type adapted to be operated primarily by exhaust steam from an engine and to be operated wholly by live steam when exhaust steam from "the engine is not available. Still more particularly the invention relates to exhaust steam injectors of the type particularly adapted to supply feed water to boilers of locomotives and having associated therewith automatic control systems for shifting the injector from live steam operation to exhaust steam operation and vise versa.

Operating experience with injectors of the above general character has demonstrated faults in operation of these injectors and the control systems therefor, among which is the tendency of the injectors to spill or break, that is, to cease proper operation, when the injector shifts as from live steam operation to exhaust steam operation, and with certain types of control systems to shift rapidly back and forth between live steam and exhaust steam operation under certain conditions of pressure of the exhaust steam available for operating the injector.

The general object of the present invention is to improve upon the control of exhaust steam injectors so as to eliminate the above-mentioned difiiculties of operation and to provide an improved control system for exhaust steam injectors which will insure continuous injector operation when the injector is shifted from live steam to exhaust steam operation and which will prevent the fluttering or chattering action of the control system in rapidly shifting back and forth from one type of operation to the other, regardless of the pressure conditions of the exhaust steam available for injector operation.

The specific nature of the invention, together with the manner in which the general object and other and more detailed objects of the in-' vention are attained, will appear more fully in the following description of a preferred form of apparatus for carrying the invention into effect,

taken in conjunction with the accompanying drawings forming a part of this specification.

In the drawings Fig. 1 is a side'elevation of part of a locomotive boiler showing the application thereto of an exhaust steam injector having a control system embodying the invention, and

Fig. 2 is a more or less diagrammaticsectional view on a large scale of a part of the injector and the control system shownin Fig. 1.

5 Referring now to Fig. 1, reference character 10 indicates the locomotive boiler and 12 is the exhaust steam injector for supplying feed water to the boiler. Water is supplied to the injector through feed pipe 14. and is delivered through the delivery pipe 16 to the boiler. I One of the en- 5 gin'e cylinders is designated at 18 and from the exhaust steam space-of the cylinder casting exhaust steam is delivered to the injector through the exhaust steam supply pipe 20. Live steam for operating the injector and for operating the 10 'control system is supplied through the pipe 22 connected to the boiler turret and controlled by the manually operable main control valve 24 located in the cab of the locomotive. Control of the amount of water fed to the boiler by the 15 injector is effected through the water regulating mechanism operated by the control handle 26 also located in thecab of the locomotive.

Turning now to Fig. 2 wherein the injector and control system are shown in detail, the in- 20 jector is of known type comprising injector body 28 providing a low pressure steam chamber 30. Co-axially mounted in the injector body are the main low pressure steam nozzle 32, the water nozzle 34 and the secondary low pressure 25 steam nozzle 36. Nozzles 32 and 36 are in communication with the steam chamber 30 and the water nozzle 34 is in communication with the water chamber 38 to which water is supplied through the feed pipe 14. Flow of water to 30 chamber 38 is controlled by the steam pressure actuated valve 40 preferably seated by means of spring 42 and adapted to be opened by piston 44 to which steam is admitted through passage 46. I 35 Flow of exhaust steam to chamber 30 is controlled by the exhaust valve 48 which in the present embodiment is of the double seated balanced type closed by spring 50 and opened by the steam actuated piston 52 to which steam 40 is admitted through the passage 54.

Live steam at high pressure is supplied from pipe 22 by way of passage 56 in the injector to a high pressure steam nozzle 58, the disr charge opening of which is located within the main low pressure steam nozzle 32. In the type of injector illustrated which is intended to deliver water against relatively high boiler pressures, a relatively small jet of high pressure live steam is employed at all times when the injector is in operation. This steam is supplied through nozzle 58 and is hereinafter termed supplementary steam. The present invention, however, is not limited in its application to injectors of the type intended to deliver against,

pipe 130.

high pressures and is equally applicable to injectors delivering against relatively low pressures and in which the supplementary steam nozzle may be omitted.

Live steam at low pressure is admitted to chamber 30 when exhaust steam is not available through passage and ports 62 around the supplementary steam nozzle 58.. This live steam of low pressurewill hereinafier'be' referredtoas auxiliary steam. i

Flow of steam to passage 60 is controlled by a double faced valve 64 located in a valve housing indicated generally at 66. Va1ve2'64 comprises .a head located in chamber 68 and has a lower face seating to close 'the'inlet of passage 60 and an upper face seatingto'clos'e communication between chamber 68 and chamber 70, the latter forming a cylinder in whichthe piston-like portion '72 of valve 64 is slidably mounted. Chamber 68 is placed in communication with the live steam supply pipe through the small orifice or choke port 74 and valve 64 is urged toward this lower seat by means of spring Chamber is placed in communication with the live steam supply from pipe 22 byway-0f passages 78 and 80 in the valve housing 66 and flow of live steam from passage 78 to passage 80 is controlled by a relay valve 82 havinga double faced head in chamber 84. At its upper end chamber 84 is vented to atmosphere or other zone of low pressure through pipe 86 and, as will be observed from the drawings, when the head of the relay valve is on'its lower seatypassage 80 and chamber 70 are vented to atmosphere and the supply oflive steam from passage '78 is prevented from reaching chamber 84. The position of relayvalve 82 is controlled by a piston portion 88 located inlchamber 90, the upper face of the piston being exposed to pressure from steam in passage 78. Chamber .90 below the piston is also placed in communication with passage '78 by means of a small ori fice or choke port 92. Chamber 90 is connected by means or pipe 94 to a pilot valve of the diaphragm actuated type contained in housing 96 and comprising a needle or pin valve 98 controlling communication between pipe 94 and vent pipe 100, the outlet end of which is preferably in communication with the low pressure steam chamber of the injector. Valve 98 is preferably arranged to be opened by spring 102 and to be closed by pressure of steam admitted to chamber 104 in the housing 96 below the diaphragm 106.

Passage 54 leading to the exhaust valve operating piston is connected by means of pipe 108 to the passage 80 connecting chambers '70 and 84. An automatically operated vent valve, the housing of which is indicated generally at 110,

connected by means of pipe 112 to the ex haust steam supply pipe 20 at a place in the latter adjacent to the exhaust valve 48 and pref erably, as shown in Fig. 2, at the lowest point in the exhaust steam supply pipe 20. This valve comprises a movable valve member 114 having piston part 116 slidably mounted in the valve casingand having a lower valve face 118 adapted to engage a seat 120 in thehousing to close communication between chamber 122 with which pipe 112 communicates and an atmospheric vent opening 124. The valve memberis urged toward open position by means of spring 126 acting on the lower face of the valve piston and chamber 128, is connected to the pipe 108 by thebranch The lift of the valve member 114 water to the injector.

from its seat, under the influence of spring 126, is preferably made adjustable and in the embodiment illustrated this adjustment is effected by means of the adjustable plug 132 in the cover of the valve housing which provides an abutment limiting the upward movement of the valve member 114. Chamber 122 extends laterally of the casing as at v1 3 1 and a pipe 136 connects the chamber portion 134 with thechamber 104 in which is located the diaphragm 106.

The major portion of the injector and control apparatus above described is known and functions in known manner as hereinafter briefly described.

new itbe assumed that exhaust steam is not "available and the injector is started by opening the main control valve 24. Live steam at high pressure flows through pipe 22 and passage 46 to act on the water valve piston to admit It also flows to the supplementary steam nozzle 58. With no exhaust steam available in the supply pipe 20 it is apparent that there will be no pressure in pipe 136 and consequently spring 102 of the diaphragm valve will act to keep this valve open. Withthe diaphragm valve open, chamber 90 below the relay valve piston is vented to a zone of low pressure through pipes 94 and 100 and high pressure steam admitted through passage 78 to 'the upper face of the relay valve piston causes the relay valve to seat against its lower seat, thus venting chamber 84 to atmosphere. This in turn vents pipe 108 to atmosphere and permits the exhaust valve to remain closed under the influence of the exhaust valve spring 50. Chamber 70 above the double seated valve 64, which maybe termed the automatic or changeover valve of the system, is also vented to atmosphere and high pressure live steam entering chamber 68 through the port .74 causes the change-over valve to seat against its upper seat, thus placing the auxiliary steam passage 60 in communication with chamber 68. Steam flows to the low pressure chamber of the ejector through passage 60 and ports 62 and is reduced in pressure by virtue of the throttling action of the choke port '74. The injector, under the assumed conditions, is thus supplied with water, high pressure supplementary live steam and low pressure auxiliary live steam and operates under these conditions as a live steam injector.

Under the assumed conditions it is to be noted that pipe leading from the automatic vent valve is vented to atmosphere by way of pipe 108 and the automatic vent valve, under the influence of spring .126, is open to vent the exhaust steam supply pipe adjacent to the injector to the atmosphere.

If, with the injector operating as a live steam injector in above described manner, exhaust steam becomes available for operating the injector the action of the control system in shifting the injector is as follows:

The presence of exhaust steam in pipe 20 causes pressure to be built up in chamber 134 (in va manner to be described more in detail later) and this pressure is transmitted to the diaphragm valve to cut off communication between pipes 94 and 100. Steam is trapped in pipe 94 and pressure is built up under the relay valve piston 88 causing the relay valve to be shifted to its upper position in which the vent 86.is closed and passages 78 and 80 are placed in communication. High pressure steam thus flows to-the chamber above the change-over valve and moves this valve to its lower seat, shutting off communication between chambers 68 and the auxiliary steam passage 60. Simultaneously, high pressure steam flows through pipe 108 to the exhaust valve piston'to open the exhaust valve and'to thereby permit exhaust steamto flow from the supply pipe 20 to the low pressure steam chamber of the injector in place of the auxiliary live steam, the supply of which has been cut off by the shifting of the change-over valve. Also, high pressure steam flows through pipe 130 and acts on the piston of the automatic vent valve to force the latter down and seat it to close the atmospheric vent 124. i

The present invention is concerned chiefly with the automatic vent'valve apparatus associated with the exhaust steam supply pipe and the manner in which this and the diaphragm valve chamber are connected into the system.

As previously mentioned, when exhaust steam injectors are shifted from live steam operation to exhaust steam operation by means of an automatically operating control system, it frequently happens that operation of the injector is interrupted and the injector must be restarted by manual manipulation of the main control valve.

The reason for this failure at times of injectors to properly shift from live steam operation to exhaust steam operation has in the past not been understood although numerous different theories have been advanced, which theories have from time to time been proved to be erroneous since the remedies indicated by such theories have failed to solve the problem of eliminating this interruption of injector operation. I have discovered that the cause of interruption in injector operation when the shift from live steam operation to exhaust steam operation takes place, and in the case of injectors operating under normal conditions and with properly adjusted parts, is due to the entry and trapping of air or other non-condensable gases in the exhaust steam supply pipe during the periods when the latter is not filled with exhaust steam. Air may enter this pipe through the exhaust passages of the engine and combustion gases from the smoke box of the boiler may be drawn into this box when the locomotive is drifting with the throttle closed, since underthese conditions the tendency is for the engine cylinders to draw gases into the exhaust passages of the engine and the condensation of steam in the supply pipe 20 tends to draw air and gases from theengine passages into this pipe. When the engine throttle is opened after a period of engine idleness, and exhaust steam flows into the supply pipe 20, it will be evident that the steam entering the pipe will tend to trap the air in this pipe and force it into the injector when the control system is operated to effect opening of the exhaust valve of the injector. Inasmuch as injectors of the character under discussion are usually installed at the rearwardend of the locomotive adjacent to the cab and the exhaust steam is supplied from the cylinder passages at the forward end of the locomotive, the exhaust steam pipe 20 must be of considerable length and consequently a considerable quantity of air may be entrapped therein. It is this quantity of entrapped air which causes the break in injector operation since under the conditions as above outlined a considerable quantity of non-condensable air and/or gas is forced into the steam chamber of the injector before the exhaust steam enters the injector. The lack of condensable low pressure steam in the injector after the auxiliary live steam supply is cut ofi due to shifting of the change-over valve causes the injector to cease to operate properly and the jet formed by the condensation of steam is destroyed.

In accordance with one phase of the present inventionthis difliculty is overcome by the provision of the automatic vent valve which vents the exhaust pipe te atmosphere when the injector is operating as a live steam injector and there is opportunity for air or other non-condensable gases to collect in the exhaust steam supply pipe.

In order to'illustrate how. the automatic vent valve eliminates the difiiculty heretofore encountered-let us consider the sequence of events which occur with the injector operating as a supplied through this pipe until the relay valve is shifted from the position it occupies when the injector is operating on live steam. Let it be assumed that the exhaust steam flow has established a-pressure in the diaphragm chamber sufiicient to close the pilot valve, thus closing the vent passage from the chamber below the relay valve piston.

In the arrangement illustrated it will be noted that the pipe 94 has a considerable volume and an appreciable length of time will elapse after closure of the pilot valve before flow of steam through the restriction 92 will cause the pressure below the relay valve to rise sufficiently to cause this valve to shift its position. In other Words, pipe 94 may be employed to provide a timing chamber which will act to delay the shifting of the relay valve with respect to the closing of the pilot valve by a period of, for example, from to seconds. During whatever delay period is provided, the automatic Thus, ample time may be provided to insure the clearing of all air and other non-condensable gases from the exhaust pipe before the exhaust valve is opened. It will be evident that from the standpoint of clearing the exhaust pipe of air and other non-condensable gases, the period of delay in individual instances may vary consid erably and in many instances this delay may not be necessary to effect change-over of operation of the injector without spilling, as the flow of exhaust steam to the injector may force substantially all of the air out of the exhaust pipe by the'time the pilot valve or other primary actuating valve of the control system is actuated.

When the exhaust valve is opened to admit exhaust steam to the injectonthe automatic vent valve is closed to prevent continued flow of exhaust steam from the supply pipe 20. Conversely, at the time when the exhaust valve is closed, the automatic vent valve is opened. In the illustrative embodiment the automatic vent valve is fluid pressure actuated and the action of this iii valve in relation to the action of the exhaust valve isobtained by connecting these valves to a common source of operating steam. .It will be evident, however, from the nature of the interaction of the two valves .that mechanical connection between the valves may be readily employed to cause one valve to be opened when the other is closed and vice versa.

By connecting the vent valve in the manner indicated, this valve also acts to drain from the exhaust pipe any condensate which may have collected in this pipe, thus insuring against the admission to the steam chamber of the injector of a quantity of water which would have to pass through the low pressure steam nozzle or nozzles of the injector.

Considering now the matter of the shifting back and forth or chattering of the control system under certain exhaust steam pressure conditions, the manner in which the present invention overcomes this difficulty may best be understood by first considering the action which takes place in the forms of apparatus as heretofore employed.

When exhaust steam is employed as the actuating medium for controlling the shifting of the injector, chattering may occur due to fluctuations in the pressure of the exhaust steam when the engine is firststarted or is operating at very low speeds. In the pastnumerous attempts have been made to provide some kind of pressure equalizing arrangement whereby these pressure fluctuations may be ironed out and a relatively steady pressure applied to the pilot valve. Experience, however, has demonstrated that the expedients of this nature heretofore resorted to are unsatisfactory in service and the difficulty has been largely overcome in the past by the provision of timing means between the pilot valve and the change-over valve acting to delay shift of the latter until a predetermined period after actuation of the pilot valve. This arrangement permits momentary closing of the pilot valve under the impulse of exhaust steam puffs before the exhaust steam pressure becomes steady, without causing the injector to be shifted to exhaust steam operation.

In accordance with one of the aspects of the present invention, the difficulty heretofore encountered in preventing chattering due to the above cause is eliminated without having to resortto timing means in the control system, because of the action of the automatic vent valve means in providing a source of comparatively steady exhaust steam pressure even under conditions of pulsating pressure in the exhaust steam supply pipe.

By reference to Figure 2 it will be evident that due to the comparatively small cross-sectional area of the passage 138 as compared with the cross-sectional areav of the chamber 134 and the outlet 1&0 from this chamber when the automatic vent valve is open, steam flowing to chamher 134 will tend to provide a relatively stable pressure in this chamber even when it is supplied thereto in puffs. When the engine is first started and puffs of steam are delivered through passage 138, the pressure'in chamber 134 will remain at too low a value to cause actuation of the pilot valve which is connected to this chamber by means of the pipe 136 and by suitably relating the cross-sectional areas of the inlet and outlet openings of this chamber, the pressure in the chamber may be maintained below that required to shift the control system until steam is suppliedthrough the inlet 138 at a rate which can be effected only by the existence in the exhaust steam pipe of a relatively steady pressure'of exhaust steam at a pressure suitable for proper injector-operation.

An important practical consideration in connection with this arrangement is that pressure equalization in chamber 134 may be obtained without having to resort to a small throttling orifice at the inlet 138, since the fact that the automatic vent valve closes immediately upon shift of the injector to exhaust steam operation renders unobjectionable a comparatively high rate of flow through chamber 134 to the atmosphere. The practical importance of this lies in the fact that, as experience has 'proven, asmall orifice employed for pressure equalizing or other purposes will soon becomeclogged and inoperative because of impurities such as carbonized lubricating oil and other foreign matter carried into the exhaust pipe by the exhaust steam from the engine. l

Another cause of chattering of the control system is caused under certain conditions by pressure drop in the exhaust pipe when the exhaust valve opened and steam admitted to the injector, and the action which takes place in apparatuses heretofore employed is substantially as follows:

Under average operating conditions experience has shown that an exhaust steam pressure ctuated diaphragm pilot valve of the type which has been found best suited for this work acts to shift the injector to exhaust steam operation when the exhaust reaches a value of approximately one and onehalf pounds per square inch and acts to shift the injector back to live steam operation when the exhaust steam pressure falls to a value of approximately one and one-quarter pounds per square inch. In other words, thereis a differential of about one-quarter pound per square inch in the pressures which cause actuation of the diaphragm valveto shift injector operation.

It is this relatively small differential pressure of one-quarter of a pound which is the cause of much of the trouble heretofore encountered with chattering, and experience has demonstrated that because of the numerous related functions of the control system it is highly impracticable to alter the present type of valve so as to alter the value of this differential pressure without incurring other difficulties in the operation of the control system.

For purposes of illustration let it be assumed that the injector is operating as a live steam injector and that the engine is running and producing exhaust steam at a pressure of less than one and one-half pounds. Further, let it be assumed that the engine is operating at sufficiently high speed so that the exhaust pressure is sub stantially uniform, that is, not pulsating. If now the engine throttle is opened slightly, increasing the exhaust steam pressure to one and one-half pounds per square inch, the injector changes to exhaust steam operation since this pressure is one of the critical pressures for the diaphragm valve. As the exhaust valve of the injector opens, exhaust steam is drawn into the injector and condensed and the flow of exhaust steam in the pipe 20 results in a pressure drop in this pipe which is reflected in the pressure existing in the diaphragm chamber. If this pressure drop exceeds one-quarter of a pound, causing the exhaust pressure acting on the diaphragm to drop steam pressure shift occurs and-the exhaust valve is closed, the

pressure in the exhaust pipe again builds up to one pound and a half (assuming that in the meantime there has been no change in the position of the main engine throttle) and the injector again shifts back to exhaust steam operation. This shift again causes pressure drop in the ex.- haust steam supply pipe due to-the opening of the exhaust valve in the injector and the shift to live steam operation again results. As long as the exhaust steam pressure conditions in the supply pipe 20 remain in the critical range, the

injector is likely to continue to shift back and. forth between live steam operation and exhaust tion to the other does not necessarily cause the injector to cease to operateproperly, even when the automatic vent valve is not employed, since this rapid shifting of operation or fluttering takes place when exhaust steam is continuously available in the exhaust steam supply pipe. The continued change-over of operation does, however, result in premature wear of the parts or" the control system, particularly the valves which have been found in practice not only to be subject to premature wear but also to be subject to premature breakage due to crystallization under the continued hammering action of rapid shifting of position and engagement with valve seats under the influence of high steam pressures.

The action of apparatus according to the present invention toeliminate this undesirable operation is as follows: v

It will be recalled that in the connection between the exhaust steam supplypipe 20 and the automatic vent valve there is provided a chamber 134 from which steam is conducted to the operating chamber of the diaphragm valve. will be evident that the area of the passage 138 leading to this chamber and the passage 140 connecting this chamber with the atmosphere may be related so that a predetermined pressure drop may be obtained between chamber 134 and the exhaust pipe 20when the .vent valve is open and steam is flowing through the vent valve under the influence of a given pressurehead in the exhaust steam supplypipe 20. Let us assume that the areas of the passages 138 and 140 are fixed to produce a pressure drop of onehalf pound per square inch between chamber 134 and the exhaust pipe when the vent valve is open and the pressure in the exhaust pipe is within therange ofirom one andyonehalf to two pounds per, square inch. Now, let

use assume that the engine is working so as to produce an exhaust steam pressure of one pound per square inch. Under this condition.

the injector will work as a live steam injector.

With live steam operation the injector exhaust,

valve is c1osed, the vent valve is open and exhaust steam is blowing through the vent valve to atmosphere. Pressure in the exhaust pipe is one pound per square inch but in the chamber 134. and consequently, in pipe 136 and the diaphragm chamber it'will. be approximately onehalf pound per square-inch less, that is, approximately one-half pound per square inch. Now

let us assume that the engine throttle is open to a degree raising the pressure in the exhaust steam pipe 20 to one and one-half pounds per square inch. This will result in a pressure in the chamber 134 of only one pound per square inch and the injector would continue to operate on live steam. When the pressure in the exhaust steam pipe reaches two pounds per square inch, a pressure of one and one-half pounds per square inch is reached in chamber 134 and since this pressure corresponds to one of the critical pressures of the diaphragm valve, the change-' over to exhaust steam operation takes place. As soon as the exhaust valve ofthe injector opens and the automatic vent valve closes, pressure of exhaust steam in the pipe'20 drops from two pounds to, let ussay, one and one-half pounds, due to the flow of steam into the injector, but since the vent valve closes substantially simultaneously with the opening of the exhaust steam valve, flow of steam through chamber 134 has ceased and the pressure in this chamber is instantly equalized with the one and one-half pound pressure which. exists in the exhaust steam supply pipe under the conditions assumed. Pressure in the pipe 136, therefore, remains at one and one-half pounds after the change to exhaust steam operation occurs and since this pressure is higher than the one and one-quarter pound diaphragm pressure which is critical with respect to change-over of operation from exhaust steam to live steam, the injector remains on exhaust steam operation and rapid shifting and chattering of the control system is pre vented.

Recalling that the injector is now operating on exhaust steam with a pressure of one and onehalf pounds in the supply pipe 20, chamber 134 and pipe 136, let it be assumed that the engine throttle is closed. until the steam pressure in I these elements drops to one and one-quarter pounds. This causes the injector to shift back to live steam operation. The exhaust valve closes and the vent valve opens. Since we have assumed that opening of the injector exhaust valve with one and one-half to two pounds pressure in the supply pipe 20 results in a pressure drop of one-half pound in this pipe, it will be evident that closing or" the exhaust valve as the; injector comes back to live steam operation will result in a rise in pressure in the exhaust steam pipe of about one-half pound. This causes the pressure in this pipe to rise from the assumed one and one-quarter pounds to approximately one and three-quarters pounds. However, when this building up of pressure in pipe 20 occurs dueto closing of the exhaust valve, the vent valve ,is open and a one-half pound pressure drop is established between pipe 20 and chamber. 1351.. Thus we have a one and three-quarter- 1 injector is open and prevents chattering of the control system.

In the case of the example just described, the apparatus provides'for change-over to exhaust steam operation at two pounds pressure and a shift: the injector toexhaust steam operation and to live steam operation may'also be varied. In the embodiment .illustrated, the amount of pressure drop provided is conveniently adjusted by means or. the adjustable plug 132. whichlimits the. lift: of the vent valve from its seat and consequently controls theiree flow area of the passage connecting the. chamber 134 with the atmosphere.

While for purposes of illustration andfor ex plaining the. nature of. the invention and the manner in which the apparatus embodying the invention operates, aspecific form of exhaust steam injector and a specific form of control system involving the use of a relay valve and an exhaust. steam pressure actuated pilot valve 7 of the diaphragm type havebeen shown, it will be evident that the invention is not limited in its application either to this specific form of injector or to this specificform of control system and may equally well be applied to other forms of injectors and control systems in which different specific arrangementsof parts are employed to obtain injection with low pressure steam and to obtain the desired shifting of theinjector from one type of operation to the'other.

It will also be evident that the construction and arrangement of the automatic vent or drain valve may be varied within the scope of the invention and that certain features of the invention may be employed to the exclusion of others. For example, the features of the prevention of chattering of the control system under difierent exhaust steam pressure conditions may be obtained through the employment of apparatus, the sole function of which is with" respect to this feature and which does not function as an apparatus for venting the exhaust pipe of air. 7

Also, it will be evident that the vent valve feature may be applied to injectors shifted by control systems operating presence or absence of high pressure steam in the line supplying the main, engine cylinders.

If applied to such systems, it is desirable to pro.- vide a timing feature in order that the exhaust valve may remain closedfor a predetermined period after live steam is admitted to theengine,

so as to insure the lapse of sufficient time before the vent valve closes to permit allof the trapped air to be vented from the exhaust steam conduit. This timing may conveniently be pro;

vided by an arrangement such as that comprising the pipe 9a in the present embodiment or an expansion chamber arrangement such as that of chamber 134 may be employed with the expansion chamber connected 'to the live steam" supply line.

What I claim is: 1. Apparatus of' the character described, comprising an exhaust steam: injector of the-typeadapted to be operated. by exhauststeam in response to the an engine and to be operated by live steam when exhaustisteam is not available, conduits for supplying-live steam and exhaust. steam to the injector, vent valve for venting the portion of the exhaust steam conduit. adjacent to the injector to prevent flow of air and non-condensable gases tothe injector through ,theexhaust steam conduit and means for causing saidvalve'to close upon shifting of the injector from live steam operation to exhaust steam operation.

2. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to .be operated by exhaust steam from an engine and to be operatedby live steam when exhaust steam is not available, conduits for supplying live steam and exhaust steam to the injector, and an automatic control system for shifting the injector from live steam operation to exhaust steam operation andvice versa, said system comprising avalve for controlling flow of exhaust steam from. the exhaust steam conduit to the. injector,-a valve for, venting the portion of. the exhaust steam conduit adjacent to the injector, and meansfor automatically closing the: second mentioned valve when the first mentioned valve is opened and for opening the second mentioned valvelwhen the. first mentioned valve is closed 3. Apparatus ofthe character described, comprising an exhaust steam injector of. the type adapted tobeoperated by'exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, conduits for supplying live steam and-exhaust steam to the injector, and a fluid pressure actuated control system for shifting the injector from live steam operation to exhaust steam operation and vice versa. comprising a fluid pressure responsive valve for controlling the flow of exhaust steam from the exhaust steam conduit to the injector and a-fluid pressure responsive valve for venting the portion of the exhaust: steam conduit adjacent to theinjector, and means for substantially simultaneously admitting pressure fluid to said valvesto causethe first mentioned valve to open and the second-mentioned valve to close when the control system is-actuated to shift the injector. from live steam operation to exhaust steam operation;

4. Apparatusof the'character described, comprising'anexhaust steam injector of the type adapted to be operated by exhaust steam from an engineand' tobe operated by'live steam when exhaust steam i's not available, conduits for supplying live steam and exhaust steam to the injector, and'acontrol systemfor automatically shifting-the-injectorfrom live steam operation to exhaust steam op'erationand vice versa, the said system comprising a valvefor controlling flow of exhaust swamp-om the exhaust steam conduit to the injector, avalve for venting a portion of the exhaust steam conduit adjacent to theinjector, the second mentioned valve being arranged to be closed'when the first mentioned valve is opened and to be opened when the first mentioned valve is closed, apilot valve for contre-lling actuatlon of'the control system, said pilot valve acting in responsetoa rise in exhaust steampressure'to a predetermined value to cause the control system to shift operation of the m jector from livesteam operation to exhaust steam operation, and timing means for delaying openinggof. thezfirstmentioned valve and closing of the second mentioned'valve for an appreciable period afteractuationioi the pilot valve due to.

rise in exhaust steam pressure to the predetermined value.

5. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, conduits for supplying live steam and exhaust steam to the injector, a'fluid pressure actuated'control system for automatically shifting the injector from live steam operation to exhaust steam operation and vice versa, said control system comprising a fluid pressure responsive valve for controlling flow of exhaust steam from the exhaust steam conduit to. the injector, a fluid pressure responsive valve for ventingthe portion of the exhaust steam conduit adjacent to the injector, the first mentioned valve being adapted to be opened by admission of pressure fluid thereto and the second mentioned valve being adapted 'to be closed by the admission of pressure fluid thereto, a pilot valve responsive to rise in pressure of the exhaust steam to a predetermined value for causing said system to shift operation of the injector from live steam to exhaust steam, fluid pressure actuated means controlled by actuation of said pilot valve for admitting pressure fluid substantially simultaneously to the two first mentioned valves, and timing means for delaying actuation of said fluid pressure actuated means ior'an appreciable period after actuation of said pilot valve due to rise of exhaust steam pressure to said predetermined value.

6. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, an exhaust steam supply conduit connecting the engine and the injector, a control system for shifting the injector from live steam operation to exhaust steam operation and vice versa, a combined vent and drain passage leading from the lowest portion of said conduit adjacent to the injector, a valve controlling flow through said passage, and means operating in response to actuation of the control system to shift the injector to exhaust steam operation for closing said valve.

'7. In apparatus of the character described, a conduit for supplying exhaust steam from an engine to an injector, a valve for controlling flow of steam from said conduit to the injector, a valve for venting the portion of the conduit adjacent to the injector to a zone of lower pressure, and means for causing substantially simultaneous'shiiting of said valves to open and close, said means being arranged to cause one of said valves to open when the other of the valves closes and vice versa. i

8. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, a conduit for supplying exhaust steam from the engine to the injector, an automatic control system including pressure responsive actuating means for shifting operation of the injector from live steam operation to exhaust steam operation and vice versa, means providing a passage leading from said conduit to a zone of lower pressure, said passage being formed so that a predetermined pressure difference is obtained between a portion of said passage and said conduit when exhaust steam is flowing through the passage, a connection for conducting actuating fluid from said portion or said passage to said pressure responsive means, a valve for controlling flow of steam through said passage, and means for closing said valve in response to actuation of said pressure responsive means to cause the control system to shift the injector from live steam operation to exhaust steam operation.

9. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, a conduit for supplying exhaust steam from the engine to the injector, an automatic control system including pressure responsive actuating means for shifting operation of the injector from live steam operation to exhaust steam operation and vice versa, means providing a chamber in communication with said conduit, having an outlet communicating with a zone of low pressure and the areas of the inlet to and the outlet from said chamber being related so that a predetermined difierence in pressure is obtained between the pressure in said chamber and the pressure in said conduit when exhauststeam is flowing through said outlet, a connection for conducting actuating fluid from said chamber to said pressure responsive means, a valve for controlling flow of steam through said outlet, and means for closing said valve in response to actuation of said pressure responsive means to cause the control system to shift the injector from live steam operation to exhaust steam operation.

10. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, a conduit for supplying exhaust steam from the engine to the injector, an automatic control system including pressure responsive actuating means for shifting operation of the injector from live steam operation to exhaust steam operation and vice versa, means providing a chamber in communication with said conduit, said chamber having an outlet communicating with a zone of low pressure and the areas of the inlet to and the outlet from said chamber being related so that a predetermined difference in pressure is obtained between the pressure in said chamber and the pressure in said conduit when exhaust steam is flowing through said outlet, a connection for conducting actuating fluid from said chamber to i said pressure responsive means, a valve for controlling flow of steam through said outlet, the position of said valve when fully open determining the area of the outlet from said chamber, adjustable means for varying the lift of the valve from its seat when in fully open position, and means for closing said valve in response to actuation of said pressure responsive means to cause the control system to shift the injector from live steam operation to exhaust steam operation.

11. Apparatus of the character described, comprising an exhaust steam injector of the type adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, a conduit for supplying exhaust steam from the engine to the injector, an automaticcontrol system including pressure responsive actuating means for shifting operation of the injector from live steam operasaid chamber tion' to exhaust steamoperation and vice versa, an automatic vent valve, means for placing said valve in communication with said conduit at a place adjacent to the injector comprising 'a connection providing a chamber havingan inlet in communication with said conduit'and an outlet controlled by said valve, the area of said outlet being related to the area of said inlet so that the pressure in said chamber when the valve is open and exhaust steam is being vented fromsaid conduit through said valve is less by predetermined amount than the pressure in saidv prising an exhaust steam injector of the type.

adapted to be operated by exhaust steam from an engine and to be operated by live steam when exhaust steam is not available, a conduit for supplying exhaust steam from the engine to the injector and an automatic control system in.- cluding actuating means responsive to exhaust steam pressure for shifting operation of the injector from live steam operation to exhaust steam operation and vice versa, means providing a passage leading from said conduit to a zone of lower pressure and having an inlet relatively restricted with respect to the. outlet, a conduit providing communication between said passage and said actuating means, and a valve for automatically closing said outlet when the control system is actuated to shift the injector to. exhaust steam operation.

13. In a control system for exhaust steam injectors, means operative when exhaust steam is available but not supplied to the injector for creating a pressure differential, means operative in response to the lower of the pressures of said pressure differential for causing admission of exhaust steam to the injector when the lower of said pressures rises to a predetermined value,

and means for equalizing said pressure differ-' ential when the exhaust steam is supplied to the injector, the second mentioned means being responsive to said equalized pressure and operating to cause the supply of exhaust steamto the injector to be shut off when said equalized pres-. sure falls to a second predetermined value. i

14. In a control system for an exhauststeam' injector, means operative when exhaust steam is available but not supplied to the injector for creating a pressure differential due to flow of exhaust steam, a pressure responsive actuating device responsive to rise of the lower of the pressures of said pressure difierential toa predetermined value to cause admission of exhaust steam to the injector, and means for, stopping said flow of exhaust steam to equalize saidpressure differential when exhaust steam is admitted to the injector, said pressure responsive actuating device being responsive to said equalized sesame pressure and-operating-tocause supply of exhaust steam to the injector to be shut off when said equalized pressure falls to a secondpredetermined value.

-15. In a control system for an exhaust steam injector adapted to receivestea-m from the exhaust steam conduit of an engine, pressure re sponsive actuating means for governing the admission of exhaust steam to the injector, means for venting to a zone of relatively low pressure a portion of the exhauststeam supplied through said exhaust steam conduit, means for causing expansion of the vented steamto a lower pressure in its path of'flow to said zone whereby to reduce the value of pressure variations of the steam, and means placing said pressure responsive actuating means in communication withthe portion of said path of flow wherein the steam,

is expanded to said lower pressure.

16. In a control system for an exhaust steam injectoradapted to receivesteamirom the exhaust steam conduit of an engine, pressure responsive actuating means for governing admission of exhaust steam to the'injector, means for venting to atmosphere aportion of the exhaust steam supplied through saidexhaust steam conduit, means for causing expansion of the vented steam to a lower pressure in its'pathof flow to atmosphere whereby to reduce the value of the pressure variations of the steam, means placing.

steam and exhaust steam to, the injector in alternation, means operative whenv exhaust steam is available but not supplied to the injector for creating a pressure difierential due to flow of exhaust steam; pressure responsive actuating means operative in response to rise of the lower of the pressures of said-pressure differential to a predetermined value for causing actuation of said automatic valve means to effect admission of exhaust steam to the injector, means for equalizing said: pressure differential when exhaust steam is supplied to the injector, said pressure responsive actuating means being responsive to said equalized pressure and causing actuation-f saidautomatic valve means to shut oiT the supply of exhaust steam to the injector when said equalized pressure falls to a second predeterminedvalue, and means for delaying the actuation of said automatic valve means by said pressure responsive actuating means to effect admission of exhaust steam to the injector.

EMANUEL RAWSON. 

